The Mystery of Manor Hall by Jane Cammack
Tom and Milly are staying at Manor Hall with Uncle Henry. Uncle Henry doesn't like teenagers, and he sometimes looks angry. Manor Hall is an old dark house with a mystery. There is a beautiful music room. But the music room is always locked and has 'Do Not Enter' on the door. One evening there is a full moon. At midnight Tom and Milly hear something. They can hear someone singing, and the noise is coming from the music room. Who is singing in the music room? What is the mystery of Manor Hall? 'We don't want to stay with Uncle Henry, Mum...